Question

The rms electric field of an EM wave is $30\sqrt{\pi}\ \text{V m}^{-1}$. Find its intensity in free space.}

• A. 30 W m$^{-2}$
• B. 3.75 W m$^{-2}$
• C. 15 W m$^{-2}$
• D. 7.5 W m$^{-2}$

Hint:

Intensity ∝ square of electric field amplitude.

Answer 1

The Correct Option is D